Waveguides for capturing close-proximity electromagnetic radiation transmitted by wireless chips during testing on automated test equipment (ATE)

ABSTRACT

A test fixture has a flexible plastic cable that acts as a waveguide. The Device-Under-Test (DUT) is a small transceiver and antenna that operate in the Extremely High-Frequency (EHF) band of 30-300 GHz. The size of the DUT transceiver is very small, limiting the power of emitted electromagnetic radiation so that close-proximity communication is used. The envelope for reception may only extend for about a centimeter from the DUT transceiver, about the same size as the test socket. A slot is formed in the test socket very near to the antenna. The slot receives one end of the plastic waveguide. The slot extends into the envelope by the DUT transceiver so that close-proximity radiation is captured by the plastic waveguide. The waveguide has a high relative permittivity and reflective metalized walls so that the radiation may be carried to a receiver that is outside the envelope.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/429,117, filed on Feb. 9, 2017, which is a continuation of U.S.application Ser. No. 14/108,708, filed on Dec. 17, 2013, all of whichare incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to test systems, and more particularly to testersthat measure electromagnetic radiation emitted by a device.

BACKGROUND OF THE INVENTION

Wireless communication devices typically feature a transmitter chip thatdrives an antenna. The antenna may be integrated inside the transmitterchip, but more commonly the transmitter chip and the antenna areintegrated onto a module or other device.

Various Automated-Test-Equipment (ATE) have been developed to test chipssuch as transmitter chips. ATE may be connected to a horn antenna todirectly measure electro-magnetic radiation emitted by the antenna.

FIG. 1 shows a horn antenna connected to an ATE to test for emittedelectromagnetic radiation from a transceiver. Interface board 120connects between ATE 128 and Device-Under-Test (DUT) transceiver 100,which may be placed into a socket (not shown) on interface board 120.

During testing, ATE 128 or other test instruments sends out stimulus orinput signals that are routed though interface board 120 to the inputsof DUT transceiver 100. Electrical outputs from DUT transceiver 100 arerouted through interface board 120 to ATE 128, which may perform variouselectrical tests such as for shorts, opens, power-supply current,programming registers, modes, and receiver and other functions. However,a primary function of DUT transceiver 100 is to drive an antenna (notshown) to emit electromagnetic radiation such as Radio-Frequency (RF)waves. The antenna may be part of a module that forms DUT transceiver100 along with a transceiver integrated circuit (IC).

When ATE 128 activates DUT transceiver 100 to transmit, electromagneticradiation waves 144 are emitted from the antenna in DUT transceiver 100.These waves 144 travel away from DUT transceiver 100. The radiatedsignal intensity and the physical geometry of the antenna causeselectromagnetic radiation waves 144 to have a pattern that may generallybe described as having an envelope 114 where radiation intensitieswithin envelope 114 are above a threshold amount, such as to bedetectable by a receiver. Envelope 114 may be a free space envelopearound DUT transceiver 100 or may be modified by structures, such as ofmetal, plastic, or dissipative materials placed near the transceiver.

Horn antenna 102 may be placed within envelope 114 to receive thesewaves 144. Horn antenna 102 has flaring metal sides shaped like a hornthat allow horn antenna 102 to collect electromagnetic radiation. Adetector at the rear of the horn receives the electromagnetic radiationthat bounces off the flared sides of the horn and into the back of thehorn. This detector converts the electromagnetic radiation intoelectrical signals that are sent to ATE 128 to evaluate the intensity ofthe electromagnetic radiation transmitted from DUT transceiver 100.

Horn antennas are especially useful for radio waves above 300 MHz.However, they tend to be large in size and bulky. Typically DUTtransceiver 100 is much smaller than horn antenna 102. Physicallyplacing a large horn antenna 102 near DUT transceiver 100 is challengingor impossible in many test environments. Thus using a large horn antennamay not be practical.

FIG. 2 shows a radiation chamber in a test environment. Some DUTtransceivers 100 may transmit with a very small power. DUT transceiver104 on interface board 120 transmits with a very low power so thatemitted electromagnetic radiation waves 144 form a smaller envelope 116.Due to the small radiated power from the DUT transmitter 104 and thepractical sizes of horn antenna 102, horn antenna 102 may not be able toadequately receive the transmitted signal. Radiation chamber 122 helpscontain the radiation and direct it to horn antenna 102. Radiationchamber 122 also blocks unwanted noise radiation from reaching hornantenna 102. Noise radiation may arise in an ATE test environment fromthe high-speed signals sent to interface board 120 or within orsurrounding ATE 128.

An opening in radiation chamber 122 is placed over DUT transceiver 104to receive smaller envelope 116. Electromagnetic radiation waves 144 maybounce off the metal walls of radiation chamber 122 until waves 144reach horn antenna 102. A detector in the rear of horn antenna 102converts these electromagnetic radiation waves into electrical signalsthat are sent to ATE 128 for evaluation.

While radiation chamber 122 may extend the range of horn antenna 102,there are still limits caused by the small radiated power of DUTtransceiver 104. The amount of electromagnetic radiation waves 144 thatfinally reach the detector in the rear of horn antenna 102 may be toolow to accurately measure the emitted radiation from DUT transceiver104. The electromagnetic radiation may be attenuated too much bymultiple bounces off of non-ideal walls within radiation chamber 122.Radiation chamber 122 may be too long or too bulky to use in a testenvironment.

A typical RF receiver that is optimized for communication over distancesin the meter to kilometer range is unlikely to be able to accuratelyreceive a signal of very low power when the receiver is not in closeproximity (0.1 mm to 20 mm) to the transmitter. The receiver should beoptimally placed in close proximity to the low-power transmitter. Theoptimal placement may be from 0.1 mm to 20 mm. This is a problem sincemany test fixtures are large and bulky, often much greater than 20 mm insize, preventing a receiver from be placed physically close enough tothe DUT transmitter being tested in the test fixture.

Lower frequencies with longer wavelengths have a larger near-fieldregion than do higher frequency signals. Thus radio waves commonly usedwith Radio-Frequency Identification (RFID) have a near-field region ofabout a few meters, but the data rates are limited by the radiofrequency to perhaps several kHz to a few MHz. Thus RFID systems tend totransmit small amounts of data, such as identifiers.

It is desired to wirelessly transmit video and other data that requirehigh data rates. RFID is too limited by the low frequency of radiowaves. The assignee has developed wireless communication systems thatuse Extremely High-Frequency (EHF) electromagnetic radiation rather thanusing Radio-Frequency (RF) electromagnetic radiation. EHF radiation hasa frequency in the range of 30 GHz to 300 GHz. This higher frequencyallows for data rates as much as 1,000 times faster than with RFtransmissions in the MHz range. However, the wavelength of radiation ismuch smaller than for current RFID systems.

Horn antenna 102 may be too bulky to be placed within 1-2 cm of DUTtransceiver 104. Horn antenna 102 may also cause undesirable loadingeffects on the transmitter and may even shift its transmitted frequency.Thus testing EHF transceivers is problematic. The amount of energy thatmay be transmitted from an antenna driven by a small IC such as used inDUT transceiver 104 may be so small that a typical receiver would not beable to adequately pick up the transmitted signal at a distance ofgreater than 20 mm.

What is desired is a test system that collects and detectselectromagnetic radiation. A test fixture that is able to directradiation to and from the DUT to a location outside the test fixture isdesired. A test method that can collect small amounts of radiation thatare only detectable within a few centimeters of the transmitting antennais desired. A low-cost method to collect small amounts of radiationemitted from a transmitter is desirable. An EHF near-field radiationcollector that can be added to an ATE is also desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a horn antenna connected to an ATE to test for emittedelectromagnetic radiation from a transceiver.

FIG. 2 shows a radiation chamber in a test environment.

FIG. 3 shows a test system with a plastic waveguide that capturesclose-proximity electromagnetic radiation emitted from a DUTtransceiver.

FIG. 4 shows a test system with a plastic waveguide that capturesclose-proximity electromagnetic radiation emitted downward from a DUTtransceiver.

FIG. 5 shows a test system with a plastic waveguide that capturesclose-proximity electromagnetic radiation emitted sideways from a DUTtransceiver.

FIG. 6 is a three-dimensional perspective view of a test fixture fortesting a DUT transceiver.

FIGS. 7A-B show slots cut in a test fixture to capture upward-directedclose-proximity radiation from a DUT transceiver.

FIGS. 8A-B show slots cut in a test fixture to capture downward-directedclose-proximity radiation from a DUT transceiver.

FIG. 9 shows a parallel test fixture for capturing close-proximityemissions from a multi-transmitter DUT.

FIG. 10 shows a parallel test fixture for capturing close-proximityemissions from multiple DUT transceivers.

FIG. 11 shows a parallel test fixture for capturing close-proximityemissions from a multiple DUT transceivers and merging capturedemissions into an antenna horn.

FIG. 12 shows an array of antenna horns that spatially multiplexcaptured radiation into a horn antenna.

FIGS. 13A-B show periodic close-proximity directors in a test fixture.

DETAILED DESCRIPTION

The present invention relates to an improvement in close-proximitytesting. The following description is presented to enable one ofordinary skill in the art to make and use the invention as provided inthe context of a particular application and its requirements. Variousmodifications to the preferred embodiment will be apparent to those withskill in the art, and the general principles defined herein may beapplied to other embodiments. Therefore, the present invention is notintended to be limited to the particular embodiments shown anddescribed, but is to be accorded the widest scope consistent with theprinciples and novel features herein disclosed.

The inventors have realized that a plastic waveguide may be used tocapture EHF electromagnetic radiation from within the near fieldenvelope and transport that radiation to a detector or receiver. Plasticmaterial with a high relative permittivity (dielectric constant of 2.0or greater) and low loss characteristics in the EHF band may be selectedso that the waves are carried for a longer distance than through air.Plastic materials such as Low-Density Polyethylene (LDPE) have suchcharacteristics. The walls of the plastic waveguide may be coated withaluminum or other metal, such as by deposition, to reflect the EHF wavesback into the plastic material. The plastic may also be surrounded withlower dielectric constant material, such as foam. The plastic materialof the waveguide may be flexible, allowing it to act as a cable carryingEHF radiation.

Testing is enabled for transmitters and receivers that are normally inclose proximity, such as between 0.1 mm and 2 cm. Close-proximitycommunication has receiving and transmitting antennas placed between 0.1mm and 2 cm from each other when transmitting through air. This distancerange of 0.1 mm to 2 cm may be modified with external components, suchas electromagnetic lens plastics, dissipative materials, and reflectivematerials.

FIG. 3 shows a test system with a plastic waveguide that capturesclose-proximity electromagnetic radiation emitted from a DUTtransceiver. DUT transceiver 10 includes antenna 12, which is drivenwith EHF signals and radiates electromagnetic radiation. The radiationmay be directional and/or polarized creating envelope 14 ofclose-proximity radiation from antenna 12. In this example, antenna 12directs emissions upward into the plastic waveguide.

Socket plunger 24 presses down on DUT transceiver 10 to keep DUTtransceiver 10 pressed into socket base 22 so that contact pins 16 onDUT transceiver 10 mate with contact pins on socket base 22. Electricalsignals generated by ATE 28 or another test equipment or test controllerdrive DUT transceiver 10 through interface board 20 and contact pins 16.When activated, DUT transceiver 10 generates electrical signals in theEHF band that are passed through antenna 12 to generate EHFelectromagnetic radiation. Socket plunger 24 or socket base 22 mayblock, attenuate, direct, or alter the electromagnetic radiationgenerated by DUT transceiver 10. Radiation may be blocked by or directedaround metal parts such as clamps, springs, and screws in socket plunger24 or socket base 22.

Slot 26 is cut, drilled, or otherwise formed in socket plunger 24 withdimensions so that one end of plastic waveguide 40 may be inserted intoslot 26. Ideally, slot 26 is directly above and aligned with antenna 12in DUT transceiver 10 so that the end of plastic waveguide 40 insertedinto slot 26 is within envelope 14 and facing antenna 12. Since theclose-proximity emissions are mostly within envelope 14, some of theseclose-proximity emissions are captured by the end of plastic waveguide40. EHF electromagnetic radiation waves 44 travel through plasticwaveguide 40. Plastic waveguide 40 may be flexible so that it may bend,allowing the EHF electromagnetic radiation waves to be directed whereverplastic waveguide 40 is placed. The metalized walls of plastic waveguide40 contain the electromagnetic radiation within plastic waveguide 40,although some signal degradation may occur.

Since the relative permittivity (Er) of the plastic material in plasticwaveguide 40 is higher than that of air, the electromagnetic radiationis more concentrated along plastic waveguide 40. The concentratedradiation is guided by the plastic waveguide, allowing radiation totravel a greater distance along plastic waveguide 40 than through theair. For example, a plastic material with a relative permittivity of 4may be selected for plastic waveguide 40, so that the EHF radiation willbe more concentrated. Metalized walls of plastic waveguide 40 containthe concentrated radiation allowing it to travel greater distances.

The length of plastic waveguide 40 may be up to several meters, comparedwith close-proximity envelope 14 which may be only 2 cm. Thus plasticwaveguide 40 allows the close-proximity electromagnetic radiation to becarried much farther than the close-proximity envelope. This resultallows the radiation detector to be placed relatively far away from DUTtransceiver 10, socket base 22, and socket plunger 24, which may berelatively large and bulky.

The other end of plastic waveguide 40 is directed onto receiver antenna32 within known-good transceiver 30. Known-good transceiver 30 may be a“gold” example of DUT transceiver 10 that has passed testing and isknown to be functional, or “good”. Interface board 34 connectsknown-good transceiver 30 to ATE 28. When electromagnetic radiationwaves 44 travel along plastic waveguide 40 and are directed ontoreceiver antenna 32, electromagnetic signals are detected on receiverantenna 32 which are detected, amplified, and output by known-goodtransceiver 30 to ATE 28. ATE 28 may compare these output signals fromknown-good transceiver 30 to an expected data pattern, or to the datapattern that DUT transceiver 10 was instructed to transmit. A datamismatch may indicate that DUT transceiver 10 is faulty, while matchingdata from known-good transceiver 30 indicates that DUT transceiver 10 isgood.

The end of plastic waveguide 40 may be held in place over receiverantenna 32 by a clamp, slot, or other fixture. During testing of a batchof DUT transceivers 10, known-good transceiver 30 is not replaced, butDUT transceiver 10 is replaced after each test procedure, with thetested DUT transceiver 10 being sorted into either a good bin or into abad bin.

FIG. 4 shows a test system with a plastic waveguide that capturesclose-proximity electromagnetic radiation emitted downward from a DUTtransceiver. DUT transceiver 10 includes antenna 12, which is drivenwith EHF signals and radiates electromagnetic radiation. The radiationmay be directional and/or polarized creating envelope 14 ofclose-proximity radiation from antenna 12. In this example, antenna 12directs emissions downward rather than upward as in the example of FIG.3.

Slot 46 is formed in socket base 22 rather than in socket plunger 24,since envelope 14 is directed downward from DUT transceiver 10 in theexample of FIG. 4. The electromagnetic radiation emitted from antenna 12may pass around contact pins 16 and into the end of plastic waveguide40.

Although plastic waveguide 40 may be flexible, it may not be able tomake a 90-degree bend as does slot 46. Plastic waveguide 40 may beforced into the horizontal part of slot 46 until its end reaches thevertical part of slot 46 under DUT transceiver 10. The end of plasticwaveguide 40 inserted into slot 46 may not be metalized, or have itsmetalization removed, so that electromagnetic radiation from antenna 12that is emitted into the vertical portion of slot 46 may enter plasticwaveguide 40. The captured radiation follows regions of higher relativedielectric constant, such as the plastic in plastic waveguide 40, andreflects off conductive surfaces, such as the outer walls of a metalizedplastic waveguide 40.

The vertical and horizontal portions of slot 46 may join with a bevelthat is metalized so that radiation moving vertically downward fromantenna 12 is reflected by 90-degrees into the horizontal slot 46 andinto plastic waveguide 40. In some applications, the radiation is ableto follow the bend between the horizontal and vertical portions withoutusing a beveled corner.

The collected radiation from plastic waveguide 40 is directed ontoreceiver antenna 32 of known-good transceiver 30. ATE 28 then comparesthe received data from known-good transceiver 30 to the data transmittedby DUT transceiver 10.

FIG. 5 shows a test system with a plastic waveguide that capturesclose-proximity electromagnetic radiation emitted sideways from a DUTtransceiver. DUT transceiver 10 includes antenna 12 driven with EHFsignals. In this example, antenna 12 directs emissions horizontally outthe side of DUT transceiver 10 rather than upward as in the example ofFIG. 3.

Slot 48 is cut or formed on the side of socket base 22, such as bydrilling a hole in socket base 22. Electromagnetic radiation is emittedby antenna 12 out the side of DUT transceiver 10, causing envelope 14 tohave a generally horizontal rather than a vertical orientation. Then endof plastic waveguide 40 inserted into slot 48 is within envelope 14 andthus captures the close-proximity radiation emitted from side-directedantenna 12. Once captured, electromagnetic radiation waves 44 travelalong plastic waveguide 40 until directed onto receiver antenna 32 inknown-good transceiver 30.

FIG. 6 is a three-dimensional perspective view of a test fixture fortesting a DUT transceiver. Socket plunger 24 is able to open and close,such as by being raised and lowered, or by pivoting about a hinge, toallow access to DUT cavity 90. DUT transceiver 10 (not shown) is placedinto DUT cavity 90 when socket plunger 24 is open. Then socket plunger24 is lowered onto socket base 22 to press DUT transceiver 10 into DUTcavity 90 so that contact pins 16 mate with contact pads inside DUTcavity 90. Once testing is completed, socket plunger 24 is again opened,allowing DUT transceiver 10 to be removed and another DUT transceiver 10placed into DUT cavity 90 for testing.

FIGS. 7A-B show slots cut in a test fixture to capture upward-directedclose-proximity radiation from a DUT transceiver. In FIG. 7A, one end ofplastic waveguide 40 is inserted into slot 26 of socket plunger 24. InFIG. 7B, plastic waveguide 40 in slot 26 collects electromagneticradiation from a DUT transceiver 10 (not shown) in DUT cavity 90 betweensocket plunger 24 and socket base 22.

FIGS. 8A-B show slots cut in a test fixture to capture downward-directedclose-proximity radiation from a DUT transceiver. In FIG. 8A, one end ofplastic waveguide 40 is inserted into slot 46 of socket base 22. In FIG.8B, plastic waveguide 40 in slot 46 collects electromagnetic radiationfrom a DUT transceiver 10 (not shown) in DUT cavity 90 between socketplunger 24 and socket base 22.

FIG. 9 shows a parallel test fixture for capturing close-proximityemissions from a multi-transmitter DUT. Multi-transmitter DUT 62contains four transceivers 60, each with an antenna (not shown) thatgenerate envelopes 14 of close-proximity EHF electromagnetic radiation.Interface board 20 drives electrical signals from ATE 28 tomulti-transmitter DUT 62 to activate the four transceivers 60 to emitradiation.

Four plastic waveguides 40 are provided, each with an end inside anenvelope 14 created by one of the four transceivers 60. The other endsof the four plastic waveguides 40 are merged together by adapter 66.Adapter 66 may be a WR-15 waveguide-to-coax converter or other similarconverter, which converts electromagnetic radiation waves intoelectrical signals that are applied to ATE 28. The four plasticwaveguides 40 may be merged together by adapter 66 or before input toadapter 66. One of the four transceivers 60 may be activated by ATE 28at a time, with the collected radiation merged and evaluated by adapter66. ATE 28 may be a 60-GHz capable coax ATE or a waveguide-basedtransmit-receive test system.

FIG. 10 shows a parallel test fixture for capturing close-proximityemissions from multiple DUT transceivers. Interface board 70 containseight test sockets 68 that may each hold a DUT transceiver 64 fortesting by signals from ATE 28. Each DUT transceiver 64 has an antenna(not shown) that generate envelopes 14 of close-proximity EHFelectromagnetic radiation. Interface board 70 drives electrical signalsfrom ATE 28 to DUT transceivers 64 to activate the transceivers to emitradiation.

Eight plastic waveguides 40 are provided, each with an end inside anenvelope 14 created by one of the eight DUT transceivers 64. The otherends of the eight plastic waveguides 40 are merged together by adapter66 or before adapter 66. Adapter 66 may be a WR-15 waveguide-to-coaxconverter, or other similar converter, which converts electromagneticradiation waves into electrical signals that are applied to ATE 28.

One of the eight DUT transceivers 64 is activated by ATE 28 at a time,with the collected radiation merged and evaluated by adapter 66. ATE 28may be a 60-GHz capable coax ATE or a waveguide-based transmit-receivetest system.

FIG. 11 shows a parallel test fixture for capturing close-proximityemissions from a multiple DUT transceivers and merging capturedemissions into an antenna horn. Interface board 70 contains eight testsockets 68 that may each hold a DUT transceiver 64 for testing bysignals from ATE 28. Each DUT transceiver 64 has an antenna (not shown)that generate envelopes 14 of close-proximity EHF electromagneticradiation. Interface board 70 drives electrical signals from ATE 28 toDUT transceivers 64 to activate the transceivers to emit radiation.

Eight plastic waveguides 40 are provided, each with an end inside anenvelope 14 created by one of the eight DUT transceivers 64. The otherends of the eight plastic waveguides 40 are each applied to antenna horn74 in an array of horns 76. Each antenna horn 74 receives the capturedradiation from plastic waveguide 40 at the small end of the horn, andemits the captured radiation in the flared or larger end of antenna horn74. The emitted radiation from the eight antenna horns 74 are collectedby horn antenna 72, which has its flared opening facing the flaredopenings of antenna horns 74. Thus radiation is spatially multiplexed bythe eight antenna horn 74 that face the opening of horn antenna 72.

One of the eight DUT transceivers 64 is activated by ATE 28 at a time,with the collected radiation merged and evaluated by horn antenna 72. Awaveguide-to-coax adapter (not shown) may be placed after horn antenna72 to provide an electrical signal to ATE 28. ATE 28 may be a 60-GHzcapable coax ATE or a waveguide-based transmit-receive test system.

FIG. 12 shows an array of antenna horns that spatially multiplexcaptured radiation into a horn antenna. Antenna horns 74 may havemetalized outer surfaces over shapes formed by a multi-layerprinted-circuit board (PCB) process. The rear of each antenna horn 74 isconnected to the end of plastic waveguide 40 that is farthest from DUTtransceivers 64. The collected radiation from plastic waveguide 40 isemitted by antenna horn 74 into the large open mouth of horn antenna 72.Thus radiation from eight plastic waveguides 40 are merged by hornantenna 72.

FIGS. 13A-B show periodic close-proximity directors in a test fixture.Metallic micro-strips 88 are formed on or near the surface of interfaceboard 20. These metallic micro-strips 88 act as Yagi directors.

Metallic micro-strips 88 are placed parallel to each other and with aspacing of a fraction of a wavelength of the carrier wave ofelectromagnetic radiation waves 44 emitted from antenna 12 in DUTtransceiver 10. For 60 GHz, metallic micro-strips 88 may have a spacingof 1.25 mm. There may be many more metallic micro-strips 88 than shownin FIG. 13A-B.

No slot is needed in socket base 22. Envelope 14 reaches the first ofthe metallic micro-strips 88, which then carry the emittedelectromagnetic waves 44 along the array of metallic micro-strips 88.Reflected electromagnetic waves 45 are then sent from the last ofmetallic micro-strips 88 to receive antenna 32 in known-good transceiver30, which is held in socket 84 on interface board 20. ATE 28 may connectto both DUT transceiver 10 and to known-good transceiver 30 throughinterface board 20.

Metallic micro-strips 88 are perpendicular to the propagation directionof electromagnetic radiation waves 44. Waves 44 may travel a distancegreater than the 1-2 cm of envelope 14. The function of plasticwaveguide 40 is performed by metallic micro-strips 88, so plasticwaveguide 40 is not needed in this embodiment.

Alternate Embodiments

Several other embodiments are contemplated by the inventors. For exampleDUT transceiver 10 may have an antenna integrated onto the same siliconor Gallium-Arsenide or other semiconductor substrate as the transceivercircuit, or an antenna that is otherwise located inside or outside thesame package as the transceiver circuit. More than one transceiver maybe integrated onto the same semiconductor substrate. The antenna couldhave a metal reflector near it to direct the electromagnetic radiationin a certain direction, such as upward or horizontally. The termsupward, downward, horizontal, vertical, etc. are relative terms and maychange with or depend on the viewer's reference frame.

While a DUT transceiver has been described, the DUT may be a transmitterwithout a receiver, or may be a transceiver with the receive functiondisabled, either permanently or temporarily. Likewise, the known goodreceiver may be a transceiver that has its transmitter disabled. In theexamples of FIGS. 3-5, known-good transceiver 30 is shown with atop-directed receiver antenna 32, which does not match the antennadirection of DUT transceivers 10 in FIG. 4, 5. A bottom or side antennamay be substituted for receiver antenna 32 in known-good transceiver 30in the examples of FIGS. 5, 6 when testing those kinds of devices, or anon-matching known-good transceiver 30 may be used as shown. A differentkind of radiation detector may replace known-good transceiver 30; thedetector does not have to be exactly the same kind of device as DUTtransceiver 10, although this may be desirable for ease of test-programdevelopment.

While contact pins 16 have been described for DUT transceiver 10, otherinterconnects may be used, such as pins, mating pads, balls, or edgeconnectors, which may be arranged in grids, lines, a perimeter, or otherarrangements. Socket plunger 24 may use springs, clips, clamps, or othercomponents to clamp DUT transceiver 10 to socket base 22. Socket plunger24 may be part of a robotic system. DUT transceiver 10 may be placedinto position when socket plunger 24 is open, then socket plunger 24 isclosed for testing. A robotic arm may move, place, insert, and removeDUT transceiver 10. Many physical configurations of socket base 22 andsocket plunger 24 are possible. Multiple DUT transceivers 10 may beplaced into a multi-socket fixture for parallel testing.

Some embodiments may delete socket plunger 24. Instead, a robotic armmay place DUT transceiver 10 into DUT cavity 90, and socket base 22 mayhave its own clamp, lever, or other component to lock DUT transceiver 10into place for testing, without the need for socket plunger 24 to pressdown on DUT transceiver 10. The function of socket plunger 24 to holdDUT transceiver 10 in place may thus be accomplished by socket base 22,and socket base 22 may be thought of as integrating both socket base 22and socket plunger 24 into the same socket fixture.

High-temperature testing could be supported by adding a heating elementto socket plunger 24 or to socket base 22. A blast of cold or hot aircould be blown onto the test fixture, or the entire test fixture couldbe placed in a temperature-controlled chamber.

Slots 26, 46, and 48 may have a variety of shapes and sizes. A plasticor other material may fill slots 26, 46, and 48 rather than have plasticwaveguide 40 pressed fully into these slots. An internal plasticwaveguide could be constructed within socket base 22 or socket plunger24 that then couples to and external plastic waveguide 40. EHFreflective material may be placed on the walls of slots 26, 46, and 48to enhance the wave-guiding properties. Alternately, cuts or holes maybe drilled into socket base 22 or socket plunger 24 to allow a flexibleplastic waveguide 40 to be inserted into envelope 14.

The slot may be a hole with a round cross-section, a rectangular holewith a rectangular cross-section, a triangular, hexagonal, or other holewith a triangular, hexagonal, or other cross-section such as any polygonor shape. The slot may be a cut made with a saw or other cutting device,or may be formed during manufacture of the test socket. An existingopening in the test socket may be used for the slot. When the testsocket does not completely cover DUT transceiver 10, and the antennadirects radiation into the non-covered part of the test socket, plasticwaveguide 40 may be clamped, glued, or otherwise held in place aboveantenna 12 without cutting a slot into the test socket since theuncovered part of the test socket acts as a pre-existing access port orslot.

Plastic waveguide 40 may be a solid flexible cable of plastic that has ahigh relative permittivity (dielectric constant) and a low loss tangent.Plastic materials are generally of low cost, reducing the cost of thetest apparatus compared with horn antennas. The length and cross-sectionof this cable may be tuned to the frequency of the electromagneticradiation, such as 60 GHz. While a plastic waveguide 40 of solid plasticmaterial has been described, a small cavity filled with air or othermaterial may be used. Plastic waveguide 40 may be made entirely from thesame plastic material, or could have regions of different plastic orother materials. Discontinuities of materials could be strategicallyintroduced for various purposes, such as to reflect, deflect, or splitelectromagnetic radiation. While metalized walls of plastic waveguide 40have been described, non-metalized walls or simply the surface of theplastic may still reflect enough electromagnetic energy to be useful.

The shapes and orientation of close-proximity radiation envelopes 14 asshown are simplified. Real radiation patterns may have variations inintensities, nodes, relative maxima and minima, may bend around objectsor through objects such as parts of socket base 22 or socket plunger 24,and may spread out or narrow in unusual ways. Actual envelopes 14 may beasymmetric and have odd shapes. Envelope 14 may be simulated or measuredwith various instruments.

As an alternative to FIGS. 9-11, a known-good transceiver 30 (FIG. 3)may be placed after the multiple plastic waveguides 40 are mergedtogether, rather than use adapter 66. Four or eight known-goodtransceivers 30 could also be used if plastic waveguides 40 are notmerged together. Some other number of DUT transceivers 64 may be testedby interface board 70. Multi-transmitter DUT 62 may contain a differentnumber of transceivers, such as 8, 2, 16, etc.

Metallic micro-strips 88 could be combined with slot 26, 46, or 48, orwith plastic waveguide 40. For example, slot 46 could direct moreelectromagnetic radiation onto metallic micro-strips 88. Metallicmicro-strips 88 could end at the first end of plastic waveguide 40,which then carries the electromagnetic radiation waves the remainingdistance to the receiver. Antenna horns 74 may be produced by a varietyof methods such as by a printing process and may be separated orintegrated onto a single substrate.

While testing of the transmit function of DUT transceiver 10 has beendescribed, the receive function could also be tested while DUTtransceiver 10 is still in socket base 22. A much larger in size andmore powerful transmitter may be used that is activated by ATE 28, andhas a much larger close-proximity envelope that can penetrate socketplunger 24. Alternately, a second test fixture could be created thatuses a known-good device for the transmitter into plastic waveguide 40,and the DUT placed on interface board 34 in place of known-goodtransceiver 30. Alternately, known-good transceiver 30 could be set totransmit, and DUT transceiver 10 set to receive, with electromagneticradiation waves 44 traveling in a reverse direction in plastic waveguide40.

Many wireless connection applications require a very small form factor,such as for a smart phone or tablet wirelessly connecting to a dock. DUTtransceiver 10 may need to be less than 1 cm per side, whileMulti-transmitter DUT 62 may need to be less than 5 cm on its longestdimension. Some applications may require that DUT transceiver 10 be only0.5 cm in the longest dimension. This small size for the transceiver andantenna severely limits the amount of power that may be radiated aselectromagnetic radiation. Envelope 14 is thus very small in size, suchas less than 2 cm before near-field effects die out.

The background of the invention section may contain backgroundinformation about the problem or environment of the invention ratherthan describe prior art by others. Thus inclusion of material in thebackground section is not an admission of prior art by the Applicant.

Any methods or processes described herein are machine-implemented orcomputer-implemented and are intended to be performed by machine,computer, or other device and are not intended to be performed solely byhumans without such machine assistance. Tangible results generated mayinclude reports or other machine-generated displays on display devicessuch as computer monitors, projection devices, audio-generating devices,and related media devices, and may include hardcopy printouts that arealso machine-generated. Computer control of other machines is anothertangible result.

Any advantages and benefits described may not apply to all embodimentsof the invention. When the word “means” is recited in a claim element,Applicant intends for the claim element to fall under 35 USC Sect. 112,paragraph 6. Often a label of one or more words precedes the word“means”. The word or words preceding the word “means” is a labelintended to ease referencing of claim elements and is not intended toconvey a structural limitation. Such means-plus-function claims areintended to cover not only the structures described herein forperforming the function and their structural equivalents, but alsoequivalent structures. For example, although a nail and a screw havedifferent structures, they are equivalent structures since they bothperform the function of fastening. Claims that do not use the word“means” are not intended to fall under 35 USC Sect. 112, paragraph 6.Signals are typically electronic signals, but may be optical signalssuch as can be carried over a fiber optic line.

The foregoing description of the embodiments of the invention has beenpresented for the purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed. Many modifications and variations are possible in light ofthe above teaching. It is intended that the scope of the invention belimited not by this detailed description, but rather by the claimsappended hereto.

We claim:
 1. A test system for testing one or more devices under test(DUTs), each DUT emitting close-proximity electromagnetic radiationcharacterized by a radiation envelope during testing, the test systemcomprising: a test socket configured to hold a DUT in place; aninterface board configured to electrically connect a test controllerwith the DUT; a first waveguide having a first end and a second end, thefirst end disposed near the test socket such that, during testing, thefirst end is within a first envelope of electromagnetic radiationcreated by a first DUT antenna included in the DUT and receiveselectromagnetic radiation emitted by the first DUT antenna; and thesecond end of the first waveguide disposed outside of the first envelopeand such that, during testing, the electromagnetic radiation emitted bythe first DUT antenna is carried by the first waveguide to the secondend.
 2. The test system of claim 1, wherein the first waveguidecomprises regions of plastic and non-plastic materials.
 3. The testsystem of claim 1, wherein the DUT comprises a plurality of transceiverintegrated circuits (ICs) with multiple antennas, wherein each antennagenerates an envelope for one of the plurality of transceiver ICs duringtesting; and the test system further comprises a plurality ofwaveguides, each waveguide disposed with respect to the test socket suchthat, during testing, a first end of each of the plurality of waveguides is situated in a radiation envelope of a different one of themultiple antennas of the DUT.
 4. The test system of claim 3, furthercomprising: an adapter receiving second ends of the plurality ofwaveguides, the adapter configured to merge electromagnetic radiationcarried by the plurality of waveguides for reception by a first receiverantenna disposed near the second end of first waveguide and by at leastone additional receiver antenna.
 5. The test system of claim 1, wherein:the first envelope is less than 2 centimeters in its longest dimension,the DUT has a longest dimension that is less than 5 centimeters, and thefirst DUT antenna has a longest dimension that is less than 1centimeter.
 6. The test system of claim 1, wherein the DUT includes anextremely high frequency (EHF) transmitter that emits EHFelectromagnetic radiation having a frequency between 30 GHz and 300 GHz.7. The test system of claim 1, wherein the DUT contains an extremelyhigh frequency (EHF) transceiver integrated circuit (IC) and the firstDUT antenna.
 8. The test system of claim 1, wherein the DUT is anintegrated circuit (IC) containing an extremely high frequency (EHF)transceiver circuit integrated onto a same semiconductor substrate withthe first DUT antenna.
 9. The test system of claim 1, wherein the testsocket includes an opening sized to receive the first end of the firstwaveguide such that, during testing, the first end is placed within thefirst envelope.
 10. The test system of claim 9, wherein the first end ofthe first waveguide is disposed over the test socket such that, duringtesting, the first end faces the DUT from above to receive theelectromagnetic radiation emitted upwards by the first DUT antenna. 11.The test system of claim 9, wherein the test socket further comprises: asocket base connected to the interface board; a DUT cavity in the socketbase configured to receive the DUT; a socket plunger situated above thesocket base, the socket plunger configured to press the DUT into the DUTcavity during testing, wherein the opening includes a first openingformed in the socket plunger such that, during testing, the firstenvelope extends into the socket plunger, and wherein the openingincludes a second opening formed in the socket base such that, duringtesting, the first envelope extends into the socket base.
 12. The testsystem of claim 11, wherein the opening is formed horizontally in a sideof the socket base such that, during testing, the first envelope extendsinto the side of the socket base.
 13. The test system of claim 1,further comprising a transceiver having a first receiver antenna,wherein: the first waveguide is configured to direct, during testing,the electromagnetic radiation emitted by the first DUT antenna onto thefirst receiver antenna in the transceiver, and the test controller isconfigured to compare data received by the transceiver with apredetermined data pattern and indicate that the DUT is faulty inresponse to the received data and the predetermined data pattern beingmismatched.
 14. The test system of claim 13, wherein the transceivercomprises a known-good transceiver being of a device type intended to bepaired with the DUT in an end-user system.
 15. The test system of claim13, wherein the transceiver is a second DUT that has passed testing, thesecond DUT substantially the same as the DUT.
 16. A test system fortesting one or more devices under test (DUTs), each DUT emittingclose-proximity electromagnetic radiation characterized by a radiationenvelope during testing, the test system comprising: a test socketconfigured to hold a DUT in place; a first waveguide having a first endand a second end, the first end disposed near the test socket such that,during testing, the first end is within a first envelope ofelectromagnetic radiation created by a first DUT antenna included in theDUT and receives electromagnetic radiation emitted by the first DUTantenna; and the second end of the first waveguide disposed outside ofthe first envelope and such that, during testing, the electromagneticradiation emitted by the first DUT antenna is carried by the firstwaveguide to the second end.
 17. The test system of claim 16, whereinthe DUT comprises: a plurality of DUTs, each DUT including: atransmitter configured to generate encoded data on a carrier wave of atleast 30 GHz, and an antenna configured to generate an envelope ofelectromagnetic radiation, and wherein the test system further comprisesa plurality of waveguides, each waveguide disposed with respect to thetest socket such that, during testing, a first end of each of theplurality of waveguides is situated in a respective radiation envelopegenerated by the antenna of one of the plurality of DUTs, and a secondend of each of the plurality of wave guides is not situated within theradiation envelope generated by each of the plurality of antennas,wherein electromagnetic radiation captured at the first end is carriedthrough each of the plurality of waveguides to the second end.
 18. Thetest system of claim 17, wherein the plurality of DUTs are integratedtogether onto a multi-transceiver module, wherein the multi-transceivermodule is inserted into the test socket.